Crown block sheave arrangement



Oct. 9, 1956 J. H. WILSON 2,766,009

CROWN BLOCK SHEAVE ARRANGEMENT Filed Oct. 5, 1954 3 Sheets-Sheet 1Inventor John Hart Wilson Oct. 9, 1956 J. H. WILSON 2,766,009

CROWN BLOCK SHEAVE ARRANGEMENT Filed Oct. 5, 1954 a Shets-Sheet 2 In 7.-I

I8 I 7 14 Inventor '1 John Hart Wilson *7 if v #0 Oct. 9, 1956 J. H.WILSON CROWN BLOCK SHEAVE ARRANGEMENT 3 Sheets-Sheet 3 Filed 001;. 5,1954 Patented Oct. 9, 1956 CROWN BLOCK SHEAVE GEMENT John Hart Wilson,Wichita Falls, Tex. Application October 5, 1954, Serial No. 460,477 2Claims. (Cl. 254-145) This invention relates to improvements in crownblocks for masts or the like, which are used in connection with rotarywell drilling rigs, and with well servicing units.

The device embodying the present invention is so designed that the axisof the traveling block is perpendicular to the front side of the mast,thereby presenting a traveling block which has one of the flat sidesthereof toward the derrick man on the racking platform, therebyminimizing the danger of his becoming entangled in the moving cables asthe traveling block raises and lowers the drill stem, pipe or the like.Also, this arrangement of the traveling block permits the derrick man toget nearer to the center of the pipe and thus reducing the distance hemust reach to attach and unlatch the pipe elevators.

Heretofore, it has been the practice to use crown blocks wherein theaxis of the traveling block was parallel with the front side of the mastpole, which arrangement resulted in the live running cables beingadjacent the derrick man, or with the axis of the traveling block at anacute angle with respect to the front of the mast, which presented acorner of the traveling block toward the derrick man, thereby presentingan awkward situation for the derrick man to work with the elevators andthe block without becoming entangled in the cable.

In the present invention, the traveling block moves up and down the mastwith the fiat side of the block toward the derrick man, therefore, hemay easily move the elevators which hang from the block, without beingin danger of the moving cables or the block.

An object of this invention is to provide a traveling block wherein theblock will always hang with the axis thereof perpendicular to the frontof the mast, or the side on which the derrick man may be working,thereby minimizing the danger of his becoming entangled within thecables, and permitting him to safely stand closer to the pipe.

Another object of this invention is to provide a sheave arrangementwhereby the sheave of the fast line is at an angle so it will point tothe center of the winding drum.

A further object of this invention is to provide a crown block, thesheaves of which are of varying diameters, with the fast line sheavebeing the larger, and the dead line sheave being smaller.

A still further object of this invention is to provide a crown block fora rotary drilling rig or for a well servicing unit, wherein thetraveling block sheaves are so arranged that they will align the axis ofthe traveling block substantially with the center of the hole, and atthe same time, a sand line sheave is provided intermediate the crownblock sheaves so the center of the groove of the sand line sheave issubstantially in a vertical plane passing through the center of the borehole of the well, but slightly to the rear thereof.

Yet another object of the invention is to provide a crown block assemblywhereby the fast line and the normal dead line may be attached to thewinding drum,

and the speed of the traveling block doubled, when desired.

A still further object of the invention is to provide a crown blockassembly in which the sheaves are so arranged that the center of gravityof all the forces acting on the top of the mast is substantially thesame as the center of gravity of the mast supporting structure in whichall the legs are the same size structural members.

With these objects in mind and others that will manifest themselves asthe description proceeds, reference is to be had to the accompanyingdrawings in which like reference characters designate like parts in theseveral views thereof, in which:

Fig. 1 is an elevational view of the front of the crown block of themast, with portions of the mast being broken away;

Fig. 2 is a view similar to Fig. 1 but taken from the side thereof;

Fig. 3 is a top plan view of the crown block, showing the sheavearrangement, and showing a portion of the mast upon which the crownblock is mounted;

Fig. 4 is a diagrammatic, top plan view showing the sheave arrangementof the crown block and showing the traveling block and the manner inwhich the cables pass therearound and therethrough, and showing portionsof the mast legs in cross-section;

Figure 4A is a fragmentary view corresponding to Figure 4, but showingboth the fast line and the normally dead line attached to the windingdrum.

Fig. 5 is a horizontal, cross-sectional view through the traveling blocktaken from above and looking down thereupon;

Fig. 6 is a side elevational view of a sheave mounting and a sheave,with parts broken away, and with one of the covers shown in raisedposition, of a typical sheave mounting on the crown block;

Fig. 7 is a top, diagrammatic view of a four line pulling arrangement ofthe crown block sheaves, showing the traveling block in relativeposition thereto, in dashed outline; and

Fig. 8 is a horizontal sectional view through a two sheave travelingblock, as shown in Fig. 7, and showing the sheaves therein.

With more detailed reference to the drawing, of the form of theinvention as shown in Figs. 1 through 6, the numeral ll designatesgenerally a structural steel, fabricated mast of a drilling rig or thelike having header beam members 2 on the upper ends of the legs of themast. A pair of brackets 4 are mounted on the upper face of the headerbeams 2, which brackets mount a shaft 5, near the upper end thereof soas to support a sheave pulley 6, of the crown block, at an angle so thatthe groove thereof will be directed substantially in alignment with thecenter of the drilling rig drum. The front face of the groove of thesheave pulley 6 will be substantially over and tangential with the faceof the traveling block sheave pulley 7, which is mounted within thetraveling block 11. The opposite face of the traveling block sheavepulley 7 is in a perpendicular plane below the face of the crown blocksheave pulley 8, which is mounted on brackets, which brackets 9 have ashaft 9a passing therethrough and through the sheave pulley 8. The crownblock sheave pulley 8 is also at an angle divergent to the crown blockpulley 6. The opposite face of the crown block sheave pulley 8 issubstantially tangential to and vertically above one face of thetraveling block sheave 10.

The opposite face of the traveling block pulley 10 is substantially invertical alignment with a face of the crown block sheave pulley 12,which sheave pulley 12 is mounted on brackets 13 and one of the brackets9. A shaft 13a passes through brackets 13 and one of the brackets 9 andjournals the sheave 12 thereon.

The opposite face of the groove of the crown block pulley 12 issubstantially above and in perpendicular alignment with one face of thesheave pulley 14 of the traveling block 11. The sheaves 7, 1i), and 14,of the traveling block 11, are journaled on shaft 15. The opposite faceof the sheave pulley 14 is substantially in perpendicular alignment witha face of the groove of crown block pulley 16, which sheave pulley ismounted on brackets 17, the brackets 17 having a shaft 17a passingtherethrough and on which shaft the sheave pulley 16 is journalled. Thecable 18 passes over sheave pulley I6 and downward to an anchor point atthe lower end of the mast, in a manner well understood in the art, orthe cable may be secured to the drum, as shown in Figure 4A, and bothlines pulled simultaneously, so as to produce more rapid movement of thetraveling block without changing the line string-up.

A sand line sheave 20 is mounted on upstanding brackets 22, whichbrackets have a shaft 24 passing therethrough near the upper endsthereof so as to journal the sheave 2i) thereon. A cable 26 passes overthe sheave 20, one end of which cable is in substantial alignment withthe center of the winding drum while the other end depends downwardsubstantially in alignment with the bore hole thereunder.

The crown block pulleys 6, 8, 12, 16, and 2% have covers 28, 39, 32, 34,and 36, respectively, which are hinged with double hinges at 35, 40, 42,44, and 46, respectively, so as to enable the cover plates to be raisedto facilitate the threading of the cable into the grooves of therespective sheaves.

Pairs of side plates 43, 5'0, 52, 54, and 56 are provided to bepositioned, one on each side of the respective sheaves 6, 8, 12, 16, and213 of the crown block, so as to enclose the sides and upper portion ofthe sheaves to prevent the workmen becoming entangled in the respectivecables 18 and 26, as they work on top of the mast.

Operation When threading up the device, the cable 18, which is known asthe fast" line, leading from the hoisting drum is passed over the backside of sheave pulley 6, of the crown block, thence downward beneathsheave pulley 7 of the traveling block and upward over the sheave pulley8 of the crown block, thence downward and under sheave pulley 19 of thetraveling block, thence upward over sheave pulley 12 and downwardbeneath sheave pulley 14, thence upward over sheave pulley 16 with thecable 18 passing downward to an anchor point A at the lower end of themast, or the cable 18 may be anchored to the drum, so both cables windsimultaaneousiy, when light loads are hoisted.

it is to be pointed out that the sheave pulley 6 is comparatively large,and since the cable 13 travels at a high rate of speed, the sheavepulley 6 will revolve comparatively slowly. The sheave pulleys 6 and 8are comparatively large and rotate at a comparatively slow speed, whichreduces the rate and amount of wear both on the line, and on thesheaves. The pulley 12 is smaller than the pulleys 6 and 3, but sincethis pulley travels at a much slower speed, little wear is accorded tothe sheave or to the cable passing thereover. By having the sheave sizesarranged in this manner, that is, with the larger sheaves 6 and 8utilized on the faster lines, and the smaller sheave 12 utilized on theslower lines, the Wear on the sheaves and cables is minimized.

The sheave 16 is normally a dead pulley, and is positioned at a point tocorrectly center the cable over the blocks and to convey it to an anchorpoint in the lower part of the mast, when a dead anchor A is used,however, when it is desired to pull light loads at high speed, both endsof the cable 18 may be attached to the winding drum, whereby the pulley16 becomes a live pulley.

By the present arrangement of the crown block pulleys, the travelingblock is always maintained in the correct working position for theworkmen, thereby minimizing the dangers incident to working in closeproximity to fast moving cables, and the cables passing outward to thewinding drum point toward the center of the winding drum.

While the form of the invention, as shown in Figs. 1 to 4, inclusive,depict a crown block using one sand line sheave and four crown blocksheaves, over which crown block sheaves a cable passes to support thetraveling block 11, it is to be understood that additional sheaves, suchas indicated at 12, may be mounted on the crown block, and be interposedin parallel relation, so that the additional sheaves, similar to thesheave 12, occupy an adjacent position to the sheave 12 intermediate thesheave 2.3 and the sheaves 16 and 20. In this manner traveling blocks ofgreater line capacity, such as eight or more lines, may be utilized, andthe traveling block, such as the traveling block 11, will maintain theflat side thereof toward the derrick man at all times.

With the sheave arrangement, as shown in Figs. 1 through 4, the centerof gravity of all the forces acting on top of the mast, including thepull of all the lines, includin the back guy lines, is indicated by acircle and designated by the numeral 58, Fig. 4. It can be seen that thecenter of gravity of these forces is very close to the center of gravityof the mast section, which means that the load is shared relativelyequally by the four legs of the mast, which results in maximum loadcapacity, while utilizing the same size and kind of material for alllegs.

The sheave mounting, as shown in Fig. 4-, permits the sheaves to beshifted and aligned with the particular points and welded in place onthe header block 2, so that the cable passing outward from the sheave tothe winding drum and downward to the traveling block is so aligned withthe winding drum and the groove of the traveling block, that minimumwear on the side flanges of the sheaves is accorded, and by having thesheaves thus arranged on mountings, which are located on the particularlocation, as shown, on top of the mast, so that the center of gravity islocated so that the load will be substantially equal on all legs of themast, thereby enabling all legs of the mast to be made of the same sidestructural material, and with the load equally distributed on all legs,a much greater load can be raised on a mast of lighter weightconstruction, than if the center of gravity were located at some otherpoint, which would cause the load to be distributed unequally on thelegs.

As shown in Fig. 4, the cable 18 passes off the pulley 6 and pointssubstantially to the center of the winding drum D positioned at adistance outward from the mast, however the distance the winding drum isfrom the mast varies in accordance with the size of the rig, and otherfactors, therefore the included angle, designated at a, usually variesfrom five degrees to fifteen degrees, depending on the distance rearwardfrom the mast the drum is mounted. The sheave 6 may be rotated about thepoint 7, which is the downwardly extending point of the cable 18, untilthe sheave 6 is in alignment with the center of the winding drum D. Itwill therefore, be seen that a sheave mounting, as shown in Fig. 4, maybe readily positioned at the particular angle, to align the sheave withthe drum and onto the traveling block, so as to maintain the travelingblock with the flat side thereof toward the man working in the mast, andat the same time, direct the cable outward to the winding drum D.

Modified form of invention Fig. 7 discloses a modified form ofinvention, which utilizes one sand line sheave 161 and three crown blocksheaves 102, 1-94, and 1-86. It is to be pointed out that these sheavesare mounted on top of the mast 1il3-105 in a manner similar to thatshown in Figs. 1, 2, and 3, however, the present sheave arrangement isstrung up for a four line block designated at 103, which will maintainthe block 108 with the flat side thereof to the derrick man, as willbest be seen in Figs. 7 and 8. In this form of the invention thesheaves:- are arranged so that the center of gravity will be asindicated by the circle at 110. The traveling block is shown to have twosheaves 112 and 114 which are journaled on shaft 116.

The sheaves are each constructed in a manner similar to the sheavesshown in Fig. 4 and are arranged so that the fast line 11% will bewithin a vertical plane passing transversely through the center of thewinding drum and with the sheaves arranged in this manner, the base 4 ofthe sheave mounting is welded to the header beams 2 of the crown block,in the manner as shown in Figs. 1 through 3.

With the sheaves arranged as shown in Fig. 7, and with the fast linepassing over sheave 102 and thence downward beneath sheave 114 intraveling block 108, thence upward over sheave 104 which is angularlydisposed so that one perpendicular face will be in alignment with aplane passing medially through the groove of pulley 114 and the otherface will lie in a plane which passes medially through the groove ofsheave 112 of the traveling block 108, and with the cable 118 passingbeneath the pulley 112, thence upward and over pulley 106, one face ofwhich groove lies in the vertical plane cutting medially through thegroove in sheave 112, the cable 118 then passes downward either to adead line anchor point A or to an anchor point on the winding drum,depending on the service required of the device.

With the cable 118 anchored to a dead line anchor point, the travelingblock 108 will move upward and downward in response to a pull on thefast line 118, in the same manner as any four line sheave arrangement,however, by connecting the dead end of the cable that passes over sheave106 to a winding drum, the block 108 is raised approximately twice asfast, but it will lift only about one-half the load weight as theaforementioned arrangement.

While the invention has been described in some detail in two formsthereof, it has been pointed out that other arrangements of sheaves maybe had, which will give the advantages of the present invention, withthe use of any number of sheaves.

Having thus described the invention, what is claimed is:

1. In a crown block arrangement for a drilling mast or the like used incombination with a winding drum on which a cable is wound, a first crownblock sheave having its axis of rotation substantially normal to a linejoining said sheave and the axial midpoint of said drum, said cableextending from said drum over said sheave, a travelling block having atleast two sheaves parallel to each other and to the flat sides of saidblock, a second crown block sheave mounted in a plane joining oppositehorizontally extreme positions of the grooves of two adjacent travellingblock sheaves, and a further crown block sheave mounted in a verticalplane and having a horizontally extreme position of its groove in avertical plane substantially parallel to a horizontal element of thefront of said mast and containing one of said opposite h0ri zontallyextreme positions of said travelling block sheave grooves, the other ofsaid opposite extreme positions being in a plane substantially parallelto said horizontal element of the front of said mast and containing thehorizontally extreme position of the groove of said first crown blocksheave on the edge thereof opposite said winding drum, said cableextending from said first crown block sheave to a travelling blocksheave thence to said second crown block sheave thence to a secondtravelling block sheave thence to said further crown block sheave,thence to an anchor point, whereby all runs of said cable betweensheaves lie in planes substantially parallel to said horizontal elementof the front of said mast.

2. A device as defined in claim 1, said travelling block having threesheaves, said device including a crown block sheave mounted in a planeparallel to the plane of said second crown block sheave and joiningopposite horizontally extreme positions of the second and thirdtravelling block sheaves.

References Cited in the file of this patent UNITED STATES PATENTS

